The present invention relates in general to products for topical application to the skin, and more particularly to improved, stable emulsions for carrying active ingredients, such as for example, Vitamin C, glycolic acid, etc., the combination of which may be packaged in gelatin capsules, preferably soft gelatin capsules, as well as other packaging structures. In particular, the invention in its broad embodiments relates to a novel polyethylene glycol (PEG) in oil emulsion. These emulsions are in the preferred mode of packaging compatible with gelatin capsules.
Vitamin C, i.e., ascorbic acid, is known as being suitable for preventing or treating a variety of skin pathologies or diseases. Vitamin C is described as being protective of damage caused by UV-A and UV-B radiation. Among the diseases that can be treated or prevented with Vitamin C therapy, i.e., antioxidant therapy, are UV-B radiation-induced erythema, photoaging of the skin, skin cancer, etc.
It is known in the art that unmodified gelatin capsules are incompatible with water. Accordingly, typical emulsions (Oil-in-Water or Water-In-Oil) will degrade a capsule shell made of gelatin. The present novel methods and combination of ingredients permit the formation of cosmetically acceptable emulsions that will be tolerated by gelatin capsules. One additional advantage of these PEG-in-oil emulsions, in combination with gelatin capsules, is the capacity for use of an increased percentage of water soluble actives that can be encapsulated versus typical anhydrous bases which cannot tolerate water soluble actives. For example, ingredients such as vitamin C, which would have a low solubility in an anhydrous base, can be incorporated at higher levels using the emulsion systems of the present invention.
However, the use of PEG as the primary solubilizer for water soluble actives in gelatin capsules is not without additional problems in need of solving. In fact, from a cosmetic aesthetic perspective, the resultant emulsion carrier would in many applications be unacceptable, as PEG has a poor feel on the skin.
Thus, one difficulty overcome in developing such an emulsion system has been the modification of a predominately PEG-based product to create a better skin feel, so that it would (a) be aesthetically acceptable to the consumer, and (b) be encapsulatable in commonly used gelatin capsules.
Accordingly, one substantial advantage of the present invention is that water soluble actives can be dissolved into PEG, emulsified into an oil base with the resultant end product having a cosmetically acceptable feel, and still be compatible in ordinary gelatin capsules.
Some of the contemplated commercial uses for the present invention would be in the area of skin treatment cosmetics. Such inventive emulsions could, for example, be used for face or body products requiring certain designated water soluble actives which would be incompatible in an anhydrous base.
Other uses, advantages and objects of the improved emulsion systems of the present invention will become known to those skilled in the art upon review of the more detailed description of the present invention set forth hereinbelow.